JonBenét was reported missing on the morning of 26 December 1996 by her mother, Patsy – who revealed to 911 operators that she had found a ransom note demanding a large sum of money for her daughter’s safe return.

But, just hours later, her husband John reported finding his daughter beaten and strangled to death in the family’s own basement.

As the ransom note demanded $118,000 (£89, 903) – the exact amount made by the Ramseys in bonuses that year – investigators suspected JonBenét’s murderer was someone very close to home. For several years, JonBenét’s mother and father were lead suspects in the case, but in 2008 they were cleared via a DNA sample taken from their daughter’s clothing. Patsy had died of cancer two years earlier, in 2006.

Prosecutors said they were "deeply sorry" for putting the family under a cloud of suspicion for more than a decade.

Images: Sundance Film Festival

Watch the chilling first trailer for Netflix's Casting JonBenét Ramsey documentary